Nature Notes: Desert Termites

BY GARY NORED

Residents of the Trans Pecos area have long been accustomed to the sight of great open spaces populated seemingly entirely by cattle – huge lumbering creatures weighing upwards of 1000 pounds apiece.  But in terms of sheer biomass, cattle are actually lightweights. In fact, a tiny creature people rarely even see exists in such numbers that their combined weight actually outweighs cattle 10 times over. 

The creature in question is the desert termite. Desert termites are more advanced than other members of the termite order and are extremely abundant. Termite colonies are everywhere, and each colony contains thousands of members. What’s more, desert termites, unlike lesser advanced termites, may house more than one reproductive female in each colony. Each female can lay 30,000 eggs a day for 20 years or more! 

Termites are what is known as a keystone species in North American deserts. Keystone species affect almost every aspect of desert life, including the types and numbers of other species that can live in the community. 

Termites perform many services for the desert.  They process nearly all of the dead plant material in the Chihuahuan Desert.  A significant portion of all nitrogen turnover in the Chihuahuan Desert passes through termites and returns to the system by way of termite predators.

The impact of termites on nitrogen availability and soil-water status significantly affects the composition and makeup of the desert plant community. Termites aerate the soil, improve water infiltration rates and reduce runoff and soil loss. 

Termites are unusual in that they cannot actually digest most of the food they eat. Lower termites feed mostly on wood and depend on various protozoans in their gut to break down the cellulose that’s the main ingredient in wood. 

Desert termites appear to have evolved the ability to digest cellulose on their own, but they still depend on bacteria to manage their nitrogen metabolism and other organisms such as fungi to digest other organic matter. 

About 85% of the termite’s diet consists of standing dead grasses, wood and leaf litter.  After summer rains dampen the soil, desert termites also consume livestock dung.  They’re so good at this function that they can consume over half of all the dung on the desert floor in a single season. During the spring and early summer, desert termites supplement their diet with live grasses.  

Termite activity usually begins in March, peaks in mid-September to early October and is over by the end of November. They are active at night and during cooler periods of the day, particularly following rains. 

If you’d like to see some of these vital creatures, go out in the evening and look for the mud tubes they build around standing vegetation. Break open a few of these “runways.” If you’re lucky you may find some white insects that look something like ants. These are foragers and warriors – members of a vast and invisible underground enterprise living directly beneath our feet.

Nature Notes presents natural wonders of the Chihuahuan Desert in this column every other week. Nature Notes is produced by the Chihuahuan Desert Research Institute and Marfa Public Radio and is sponsored by the Meadows Foundation and the Dixon Water Foundation. Tune in to Nature Notes on KRTS-93.5 FM on Tuesdays and Thursdays at 8:35 a.m. and 4:45  p.m. and again on Thursdays at 7:06 p.m.